The StarWars lore apparently has an established category called UGLY which referes to boot legged strapped together amalgamations of multiple crafts into one.

Here's the WIKI explanation;
http://starwars.wikia.com/wiki/Ugly/Legends

I put the wings and blasters of a Tie interceptor onto an X-Wing body.
The Body still has its torpedo launchers and hyperdrive engines as you can see.

I'd speculate the boot legged wing replacement is either a performance downgrade or some sort of stat trade, but most likely a net loss of performance unless those are really good Intorceptor wings.